Migration Drivers

Database-specific DDL generation, schema introspection, and type mapping

What Migration Drivers Do

Schema introspection - Read current database state
DDL generation - Generate database-specific SQL
Type mapping - Convert VibORM types to database types
Capability detection - Handle database-specific limitations

Available Drivers

Driver	Database	Native Enums	Native Arrays	Index Types
PostgreSQL	PostgreSQL	Yes	Yes	btree, hash, gin, gist
MySQL	MySQL	Yes (inline `ENUM`)	No (JSON)	btree, fulltext, spatial
SQLite	SQLite, LibSQL	No (CHECK)	No (JSON)	btree

Each driver declares what its database can do: whether enums and arrays are native, which index types exist, and whether enum values can be added inside a transaction. PostgreSQL has native enum types and arrays but can’t run ALTER TYPE ... ADD VALUE inside a transaction. MySQL defines enums inline on the column (changing one is a MODIFY COLUMN, which implicitly commits) and stores arrays as JSON. SQLite emulates enums with CHECK constraints and stores arrays as JSON.

Supported Operations

Migration drivers generate DDL for these operations:

Operation	PostgreSQL	MySQL	SQLite
`createTable`	Direct	Direct	Direct
`dropTable`	Direct	Direct	Direct
`renameTable`	Direct	Direct	Direct
`addColumn`	Direct	Direct	Direct
`dropColumn`	Direct	Direct	Direct (3.35.0+)
`renameColumn`	Direct	Direct	Direct (3.25.0+)
`alterColumn`	Direct	`MODIFY COLUMN`	Table recreation
`createIndex`	Direct	Direct	Direct
`dropIndex`	Direct	Direct	Direct
`addForeignKey`	Direct	Direct	Table recreation
`dropForeignKey`	Direct	Direct	Table recreation
`addPrimaryKey`	Direct	Direct	Table recreation
`dropPrimaryKey`	Direct	Direct	Table recreation
`createEnum`	`CREATE TYPE`	No-op (inline in column)	No-op (TEXT)
`dropEnum`	`DROP TYPE`	No-op	No-op
`alterEnum`	`ALTER TYPE`	`MODIFY COLUMN` per column	No-op

Automatic Driver Selection

VibORM automatically selects the migration driver based on your database driver:

import { createClient } from "viborm/postgres";

const client = createClient({
  databaseUrl: "...",
  schema: { User },
});

// PostgreSQL migration driver is automatically used
await push(client);

Type Mapping

Each driver maps VibORM scalar types to database-specific types:

Common Mappings

VibORM Scalar	PostgreSQL	MySQL	SQLite
`string()`	`text`	`TEXT`	`TEXT`
`int()`	`integer`	`INT`	`INTEGER`
`bigint()`	`bigint`	`BIGINT`	`INTEGER`
`float()`	`double precision`	`DOUBLE`	`REAL`
`boolean()`	`boolean`	`TINYINT(1)`	`INTEGER`
`datetime()`	`timestamp`	`DATETIME(3)`	`TEXT`
`json()`	`jsonb`	`JSON`	`TEXT`
`blob()`	`bytea`	`BLOB`	`BLOB`

See individual driver pages for complete type mappings.

Next Steps

PostgreSQL Driver

MySQL Driver

SQLite Driver